Design of a nested eight-channel sodium and four-channel proton coil for 7T knee imaging

Ryan Brown, Guillaume Madelin, Riccardo Lattanzi, Gregory Chang, Ravinder R. Regatte, Daniel K. Sodickson, Graham C. Wiggins

    Research output: Contribution to journalArticlepeer-review


    The critical design aim for a sodium/proton coil is to maximize sodium sensitivity and transmit field homogeneity while simultaneously providing adequate proton sensitivity and homogeneity. While most dual-frequency coils use lossy high-impedance trap circuits or PIN diodes to allow dual-resonance, we explored a nested-coil design for sodium/proton knee imaging at 7 T. A stand-alone eight-channel sodium receive array was implemented without standard dual-resonance circuitry to provide improved sodium signal-to-noise ratio. A detunable sodium birdcage was added for homogeneous sodium excitation and a four-channel proton transmit-receive array was added to provide anatomical reference imaging and B0 shimming capabilities. Both additional modules were implemented with minimal disturbance to the eight-channel sodium array by managing their respective resonances and geometrical arrangement. In vivo sodium signal-to-noise ratio was 1.2-1.7 times greater in the developed eight-channel array than in a mononuclear sodium birdcage coil, whereas the developed four-channel proton array provided signal-to-noise ratio similar to that of a commercial mononuclear proton birdcage coil.

    Original languageEnglish (US)
    Pages (from-to)259-268
    Number of pages10
    JournalMagnetic resonance in medicine
    Issue number1
    StatePublished - Jul 2013


    • cartilage
    • dual-tuned coil
    • high-field sodium MRI
    • phased-array

    ASJC Scopus subject areas

    • Radiology Nuclear Medicine and imaging


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